The half life is 138 days, meaning exactly half of the material will decay after this time. Use this information to find the decay factor
:

Then after 250 days, there will be

grams left.
C. Multiply and add
Cost = (3×21.99)+45.99
Cost = $111.96
Answer:
954.56 in²
Step-by-step explanation:
A = 2×π·r² + 2·π·r·h
= 2×3.14×64 + 2×3.14×8·11
= 401.92 + 552.64
= 954.56 in²